1. Field of the Invention
The present invention pertains to a computer system for operating virtual servers on physical servers, and in particular, to a method of and an apparatus for measuring a margin of processing performance or capacity of each physical server.
2. Description of the Related Art
There has been known a virtual server technique to use one computer virtually as a plurality of servers by making a plurality of operating systems (OS) operate on one single physical server, i.e., a computer such as a workstation or a personal computer. Products employing such technique include “VMWare ESX Server” of VMWare, “VirtualServer” of Microsoft, and “Xen” of XenSource. According to these products, a new virtual server can be created on a physical server when a virtual server creation command is issued. Articles regarding the technique to generate a virtual server on a physical server include, for example, Japanese Patent Application Laid-Open No. 2005-115653 (document 1).
There also exists a known technique for use in a distributed processor environment including a plurality of physical servers communicably connected via a network to each other wherein a virtual server is automatically or manually moved from a first physical server to a second physical server depending on, for example, utilization efficiency of a resource or workload. In this connection, for example, document 1 and Japanese Patent Application Laid-Open No. 10-283210 (document 2) describe such server moving technique. “Vmotion” of WMWare and “migration” of Xen provide a virtual server moving function.
To create a new virtual server on a physical server or to move a virtual server from a first physical server to a second physical server in the virtual server environment including a plurality of physical servers, a check is made to determine whether the physical server in which the virtual server is to be created or the second physical server as the destination of the virtual server includes a free resource available for the virtual server. If such resource is present therein, the creation or the movement of the virtual server is carried out. Reference is to be made to, for example, paragraphs 33 to 35 of document 1, and paragraph 20 of document 2.
According to a conventional technique regarding the measurement of performance of a physical server as described in, for example, Japanese Patent Application Laid-Open No. 2006-18710 (document 3), a management computer installs a performance measurement program in a plurality of management target computers and executes the program therein to collect results of execution of the program. According to a well-known technique to make a comparison with respect to performance between two computers including mutually different Central Processing Units (CPU) and Operating Systems (OS), a benchmark program is executed on both computers to compare results of the program execution with each other. Also in a virtual server environment including a plurality of physical servers, there exists a situation in which the benchmark of each physical server is employed as described in, for example, paragraph 17 of document 1. Additionally, as described in paragraph 31 of document 1, each virtual server operating on the physical servers executes a program other than the application programs to gather performance data items such as a CPU utilization ratio and a period of time required to execute predetermined calculation processing. The results of the program execution are delivered to a management server together with a virtual server IDentifier (ID) and data of time associated with the program execution. The results and these data pieces are stored in a database. In accordance with document 1, the performance data items recorded at respective points of time of each virtual server are adopted to determine whether a virtual server in consideration was in operation at the points of time.
As described above, if the physical server includes an available resource equal to or more than a resource required for the virtual server to be created or the virtual server to be moved, it is assumed that the physical server has a margin of processing performance to operate the virtual server. However, in physical servers mutually having almost the same resource margin, it is not necessarily guaranteed, due to a variety of CPUs and operating systems (OS), and the number and a variety of virtual servers in operation, that the virtual server initiated as a new server operates with expected performance on the physical servers. Therefore, a new performance measuring method is required to draw a comparison with respect to the processing performance margin between the physical servers according to a criterion other than the resource margin.
A benchmark test for each physical server is effective to make a comparison in performance between the physical servers. However, in a virtual server environment in which the host operating system varies in each physical server, in order to conduct the performance measurement according to one and the same criterion, it is required to prepare a common benchmark program for different host operating systems for the following reason. When benchmark programs differ, the measurement criterion and precision varies even though the object of measurement is the same. This leads to a disadvantage that the results of the benchmark test cannot be directly compared with each other.
According to document 1, each virtual server operating on each physical server periodically executes a performance measurement program other than the application programs to collect results of the program execution. However, the results only serve as an indication of performance of the virtual server, but cannot be an indication of a margin of the processing performance of the physical server. Moreover, the virtual servers operating on the respective physical servers may not employ the same operating system, and hence it is not guaranteed that the measurement is carried out according to the same criterion.